Ionized zinc vacancy mediated ferromagnetism in copper doped ZnO thin films

摘要

This paper reports the origin of ferromagnetism in Cu-doped ZnOthin films. Room-temperature ferromagnetism is obtained in all the thin films when deposited at different oxygen partial pressure. An obviously enhanced peak corresponding to zincvacancy is observed in the photoluminescence spectra, while the electrical spin resonance measurement implies the zincvacancy is negative charged. After excluding the possibility of direct exchange mechanisms (via free carriers), we tentatively propose a quasi-indirect exchange model (via ionized zincvacancy) for Cu-doped ZnO system.